《什么是过滤.ppt

二、承托层 作用： 阻挡滤料进入配水系统 均匀配水（反冲洗时） 主要配合大阻力配水系统而使用。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 第4节 配水系统与反冲洗 配水系统的目的： 均匀分布反冲洗水 均匀收集过滤水 配水不均匀导致： 1）部分区域水量小，冲洗不净 2）部分区域水量大，冲动垫层 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 一、配水系统的不均匀性 Hx 冲洗水头 a b Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. a点的冲洗水头Hx： Hx＝S1a(qa?a)2+S2(?aqa)2 +S3(?aqa)2 + S4(?aqa)2＋流速水头 S1：配水系统的阻力系数 S2：孔眼出水的阻力系数 S3：承托层的阻力系数 S4：滤料层的阻力系数 qa：冲洗强度 (L/(s m2)) Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 同样对于b点而言： Hx＝S1b(?bqb)2+S2(?bqb)2 +S3(?bqb)2 + S4(?bqb)2＋流速水头 q最小/q最大?0.95-------达到均匀 两种途径：1）增大孔眼出水水力阻抗 2）降低配水系统水力阻抗 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 二、配水系统类型 1．大阻力配水系统 使孔眼水力阻力S2其它水力阻力 ?增加孔眼流速（5－6m/s） ?配水孔眼面积为滤池面积的1/500 ?开孔比小＝0.2－0.25% Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 一般为穿孔管大阻力配水系统。 特点：工作可靠、采用最广、冲洗干净 但冲洗水头要求高，需冲洗水箱或水泵 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 2．小阻力配水系统 减少配水系统阻抗S1 ?降低配水系统流速 ?增大配水空间 ?使孔眼处的压力接近 ?相应降低S2，增加开孔比1.0-1.5% 指孔口阻力较小 特点：配水系统结构简单，冲洗水头小（2m左右） 适应于面积小的滤池 中阻力配水（开孔比：0.6-0.8%） Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 钢筋混凝土穿孔板：板上铺设一层或两层尼龙网。 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 穿孔滤砖：开孔比，上层1.07％，下层0.7% Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 滤池穿孔滤砖 Evaluation only. Created with Aspose.Slides for .NET 3.5 Clien